Haptic effect enabled system using fluid

ABSTRACT

A haptic effect enabled system generates a haptic effect using an electric potential responsive fluid. A haptic enabled apparatus includes a fluid and a substrate. The fluid is responsive to an electric field. The substrate is at least partially flexible and defines a channel. The fluid is positioned within at least a portion of the channel. A portion of the substrate proximal to the fluid is stiffer than a portion of the substrate spaced from the fluid, thereby creating a haptic effect.

BACKGROUND

Haptic effects are used to enhance the interaction of an individual witha haptic-enabled device such as electronic devices, wearable articles,or other types of things. They are delivered through haptic actuatorsand typically enable the user to experience a tactile sensation. Hapticeffects can be used to simulate a physical property or to deliverinformation such as a message, cue, notification, or acknowledgment orfeedback confirming a user's interaction with the haptic-enabled device.However, such haptic actuators consume power, which is at a premium inbattery operated articles such as phones, controllers, tables, and thelike. Additionally, state-of-the art haptic actuators do not always havea form factor or the flexibility that lends itself to discreteimplementations in applications other than traditional electronicdevices such as clothing, wrist bands, and other types of wearablearticles.

SUMMARY

In general terms, this disclosure is directed to a haptic actuator thatuses fluid to increase the stiffness of a flexible substrate to delivera haptic effect.

One aspect is a haptic enabled apparatus including a fluid and asubstrate. The substrate is at least partially flexible and defines achannel. The fluid is positioned within at least a portion of thechannel. A portion of the substrate proximal to the fluid is stifferthan a portion of the substrate spaced from the fluid. The fluid movesthrough the channel in response to a predetermined field, and thestiffness of the substrate changes in response to the moving fluid todeliver a haptic effect.

Another aspect is a method of automatically generating a haptic effect.The method comprises: generating a field, the field embodyinginformation to communicate to a user through a haptic effect; movingfluid through a channel defined in a flexible substrate in response tothe field; increasing the stiffness of at least a portion of thesubstrate in response to the fluid moving through the channel, theincreased stiffness generating the haptic effect and communicating theinformation.

Another aspect is a haptic enabled apparatus wearable by a person. Theapparatus comprises a wearable article and a fluid responsive to afield. The fluid comprises a liquid metal and an electrolyte. Asubstrate is operably connected to the wearable article, and thesubstrate is at least partially flexible and defines a channel. Thefluid is positioned within at least a portion of the channel, and aportion of the substrate proximal to the fluid is stiffer than a portionof the substrate spaced from the fluid. First and second electrodes areproximal to opposite ends of the channel. A controller is electricallyconnected to the first and second electrodes and is configured togenerate an electrical signal. The electrical signal embodiesinformation to communicate through a haptic effect. The electricalsignal generates a field when applied to the first and secondelectrodes. When the field has one polarity, an oxide is deposited onthe liquid metal and the liquid metal flows through the channel in onedirection and increases stiffness of the substrate to deliver the hapticeffect and communicate the information. When the field has an oppositepolarity, the oxide is removed from the liquid metal and the liquidmetal flows through the channel in an opposite direction and stiffnessof the substrate is decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a haptic enabled system in accordance withan exemplary embodiment of the present disclosure.

FIG. 2 illustrates a more detailed block diagram of a possibleembodiment of the haptic enabled device as illustrated in FIG. 1.

FIG. 3 is a block diagram illustrating a networked environment in whichthe haptic enabled devices illustrated in FIGS. 1 and 2 can operate.

FIG. 4A is a schematic diagram of an exemplary embodiment of the hapticactuator.

FIG. 4B is a cross sectional view of the haptic actuator of FIG. 4A.

FIG. 5 is a schematic cross sectional view of an alternative example ofthe haptic actuator.

FIGS. 6A-6D illustrate operation of fluid in the actuator when under anelectrical potential.

FIG. 7 schematically illustrates a side view of the substrate todescribe a stiffness of the substrate.

FIG. 8 schematically illustrates another exemplary embodiment of thehaptic actuator.

FIGS. 9A and 9B schematically illustrate other exemplary embodiments ofthe haptic actuator.

FIG. 10 is a schematic diagram of another exemplary embodiment of thehaptic actuator.

FIGS. 11A and 11B are schematic diagrams of yet another exemplaryembodiment of the haptic actuator.

FIG. 12 schematically illustrates an example application of the hapticenabled device.

FIG. 13 schematically illustrates another example application of thehaptic enabled device.

FIG. 14 schematically illustrates yet another example application of thehaptic enabled device.

DETAILED DESCRIPTION

Various embodiments will be described in detail with reference to thedrawings, wherein like reference numerals represent like parts andassemblies throughout the several views. Reference to variousembodiments does not limit the scope of the claims attached hereto.Additionally, any examples set forth in this specification are notintended to be limiting and merely set forth some of the many possibleembodiments for the appended claims.

Whenever appropriate, terms used in the singular also will include theplural and vice versa. The use of “a” herein means “one or more” unlessstated otherwise or where the use of “one or more” is clearlyinappropriate. The use of “or” means “and/or” unless stated otherwise.Terms such as “comprise,” “comprises,” “comprising,” “include,”“includes,” “including,” “such as,” “has,” and “having” areinterchangeable and not intended to be limiting. For example, the term“including” shall mean “including, but not limited to.”

In general, the present disclosure relates to a haptic-enabled apparatusthat employs a fluid to generate a haptic effect. In an exemplaryembodiment, the apparatus comprises a substrate that defines a channelthrough which the fluid can flow. A pump mechanism moves the fluidthrough the channel. As fluid moves through the channel, pressureincreases in the portion of the channel proximal to the fluid and theportion of the substrate proximal to the fluid becomes stiffer. Such achange in stiffness can deliver a tactile sensation to a user and thusdeliver a haptic effect. As discussed in more detail, the pump mechanismcan be any type of mechanism, electrochemical process, capillarymechanism, or other phenomenon or action that can cause fluid to flow.Examples of such pump mechanisms and processes include electrodes,electrochemical reactions, and mechanical mechanisms.

A haptic effect can be any type of tactile sensation delivered to aperson. In some embodiments, the haptic effect embodies information suchas a cue, notification, feedback or confirmation of a user's interactionwith a haptic-enabled article, or a more complex message or otherinformation. In alternative embodiments, the haptic effect can be usedto enhance a user's interaction with a device by simulating a physicalproperty or effect such as friction, flow, and detents.

FIG. 1 illustrates a block diagram of one of many possible embodimentsof a haptic-enabled article 100. In the specific embodiments disclosedherein, the haptic-enabled article 100 is a wearable article thatincludes a haptic actuator 102, a controller 104, and an input device106. The haptic enabled article 100 can be any type of article that canbe used to deliver haptic effects to a person. For example, thehaptic-enabled article 100 can be a wearable article such as shirts;pants; shoes and other footwear; coats, jackets and other outerwear;hats; belts and suspenders; neckties; scarves; athletic equipment;safety and protective equipment such as helmets, protective vests, andbody armor; medical devices and fitness trackers such as heart ratemonitors, pedometers, ambulatory infusion pumps, glucose meters, insulinpumps; jewelry; watches and watchbands; eyeglasses and goggles; virtualreality headsets; prosthetics such as artificial limbs; accessories suchas purses and wallets; and anything else that can be carried on the bodyor in clothing. Although wearable articles are disclosed herein, thehaptic-enabled article 100 also can be other things such as cell phones;computers; tablets; electronic games; game controllers; pointers such amouse or pen; cases and covers for electronic devices; and other thingsand electronic devices.

In some embodiments and as illustrated in FIG. 1, the actuator 102, thecontroller 104, the input device 106, and the haptic enabled article 100are incorporated into a single device, which can be worn or carried by auser. In other embodiments, at least one of the actuator 102, thecontroller 104, and the input device 106 are separately arranged fromthe others and connected to each other either wirelessly or by wire.

The controller 104 is any type of circuit that controls operation of theactuator 102 based on receiving a signal or data from the input device106. Data can be any type of parameters, instructions, flags, or otherinformation that is processed by the processors, program modules, andother hardware disclosed herein.

The input device 106 operates to monitor or detect one or more eventsassociated with a user of the haptic enabled article 100, or performedby the user, of which the user can be informed with a haptic feedback.The input device 106 is any device that inputs a signal into thecontroller 104. An example of an input device 106 is a control devicesuch as a switch or other type of user interfaces. Another example of aninput device 106 is a transducer that inputs a signal into thecontroller 104. Examples of transducers that can be used as an inputdevice 106 include antennas and sensors. Various embodiments can includea single input device or can include two or more input devices.Additionally, various embodiments can include different types of inputdevices. For example, at least some possible embodiments include aswitch and a transducer such as an antenna or a sensor. When the inputdevice 106 is stimulated and inputs a signal to the controller 104, thecontroller 104 operates the actuator 102 to provide a haptic effect tothe person wearing or interacting with the article 100.

FIG. 2 illustrates a more detailed block diagram of a possibleembodiment of the haptic enabled article 100 (also referred to herein asa wearable article) as illustrated in FIG. 1.

In this embodiment, as discussed in FIG. 1, the article 100 includes thehaptic actuator 102, the controller 104, and the input device 106.Examples of the input device 106 can include one or more user interfacedevices 110, a sensor 112, and an antenna 113. Various embodiments caninclude just one of these input devices 106 or combinations of a userinterface 110, sensor 112, or antenna 113. Various embodiments also caninclude multiple input devices of the same type. For example, anembodiment can include two sensors 112. The input device 106 is inelectrical communication with the controller 104. An actuator drivecircuit or device 114 is in electrical communication with the controller104 and the actuator 102.

Various embodiments of the actuator 102 are disclosed in more detailherein. An advantage of the actuators 102 disclosed herein is that theyimprove flexibility and require less power to be actuated than manyother types of haptic actuators.

The user interface devices 110 include any device or mechanism throughwhich a user can view information, or input commands or otherinformation into the haptic enabled article 100. Examples of userinterface devices 110 include touchscreens, cameras, mechanical inputssuch as buttons and switches, and other types of input components.

The sensor 112 can be any instrument or other device that outputs asignal in response to receiving a stimulus. The sensor 112 can behardwired to the controller 104 or can be connected to the controller104 wirelessly. The sensor 112 can be used to detect or sense a varietyof different conditions, events, environmental conditions, the operationof condition of an article, the presence of other people or objects, orany other condition or thing capable of stimulating a sensor.

Examples of sensors 112 include acoustical or sound sensors such asmicrophones; vibration sensors; chemical and particle sensors such asbreathalyzers, carbon monoxide and carbon dioxide sensors, and Geigercounters; electrical and magnetic sensors such as voltage detectors orhall-effect sensors; flow sensors; navigational sensors or instrumentssuch as GPS receivers, altimeters, gyroscopes, or accelerometers;position, proximity, and movement-related sensors such as piezoelectricmaterials, rangefinders, odometers, speedometers, shock detectors;imaging and other optical sensors such as charge-coupled devices (CCD),CMOS sensors, infrared sensors, and photodetectors; pressure sensorssuch as barometers, piezometers, and tactile sensors; force sensors suchas piezoelectric sensors and strain gauges; temperature and heat sensorssuch as thermometers, calorimeters, thermistors, thermocouples, andpyrometers; proximity and presence sensors such as motion detectors,triangulation sensors, radars, photo cells, sonars, and hall-effectsensors; biochips; biometric sensors such as blood pressure sensors,pulse/ox sensors, blood glucose sensors, and heart monitors.Additionally, the sensors 112 can be formed with smart materials, suchas piezo-electric polymers, which in some embodiments function as both asensor and an actuator.

The actuator drive circuit 114 is a circuit that receives a hapticsignal (also referred to herein as a drive signal) from the controller104. The haptic signal embodies haptic data associated with hapticeffects, and the haptic data defines parameters the actuator controlcircuit 114 uses to generate a haptic actuation signal. In exemplaryembodiments, such parameters relate to, or are associated with,electrical characteristics. Examples of electrical characteristics thatcan be defined by the haptic data includes frequency, amplitude, phase,inversion, duration, waveform, attack time, rise time, fade time, andlag or lead time relative to an event. The haptic actuation signal isapplied to the actuator 102 to define movement of fluid in the actuator102 and thus provide one or more haptic effects.

In one embodiment, the haptic actuation signal is a signal that appliesa potential across two or more electrodes as discussed in more detailherein. In other embodiments, the actuation signal is applied to anddrives an electromechanical pump or other possible pumping mechanism.

The controller 104 comprises a bus 116, processor 118, input/output(I/O) controller 120, and memory 122. The bus 116 includes conductors ortransmission lines for providing a path to transfer data between thecomponents in the controller 104 including the processor 118, memory112, and I/O controller 120. The bus 116 typically comprises a controlbus, address bus, and data bus. However, the bus 116 can be any bus orcombination of busses, suitable to transfer data between components inthe controller 104.

The I/O controller 120 is circuitry that monitors operation of thecontroller 104 and peripheral or external devices such as the userinterface devices 110, the sensor 112 and the actuator drive circuit114. The I/O controller 120 also manages data flow between thecontroller 104 and the peripheral devices and frees the processor 118from details associated with monitoring and controlling the peripheraldevices. Examples of other peripheral or external devices with which theI/O controller 120 can interface includes external storage devices;monitors; input devices such as keyboards and pointing devices; externalcomputing devices; antennas; other articles worn by a person; and anyother remote devices.

The processor 118 can be any circuit configured to process informationand can include any suitable analog or digital circuit. The processor118 also can include a programmable circuit that executes instructions.Examples of programmable circuits include microprocessors,microcontrollers, application specific integrated circuits (ASIC),programmable gate arrays (PLA), field programmable gate arrays (FPGA),or any other processor or hardware suitable for executing instructions.In various embodiments, the processor 118 can be a single unit or acombination of two or more units. If the processor 118 includes two ormore units, the units can be physically located in a single controlleror in separate devices.

The memory 122 can include volatile memory such as random access memory(RAM), read only memory (ROM), electrically erasable programmable readonly memory (EEPROM), flash memory, magnetic memory, optical memory, orany other suitable memory technology. The memory 122 also can include acombination of volatile and nonvolatile memory.

The memory 122 can store a number of program modules for execution bythe processor 118, including an event detection module 124, a hapticdetermination module 126, a haptic control module 134, and acommunication module 130. Each module is a collection of data, routines,objects, calls, and other instructions that perform one or moreparticular task. Although certain modules are disclosed herein, thevarious instructions and tasks described herein can be performed by asingle module, different combinations of modules, modules other thanthose disclosed herein, or modules executed by remote devices that arein communication, either wirelessly or by wire, with the controller 104.

The event detection module 124 is programmed to receive data from thesensor 112, the antenna, or a remote device. Upon receiving the data,the event detection module 124 determines whether the received datarelates to an event, condition, or operating state associated with ahaptic effect.

Upon identification of an event associated with a haptic effect, thehaptic determination module 126 analyzes the data received from thesensor 112, antenna, or remote device to determine a haptic effect todeliver through the actuator 102. An example technique the hapticdetermination module 126 can use to determine a haptic effect includesrules programmed to make decisions to select a haptic effect. Anotherexample includes lookup tables or databases that relate haptic effectsto data received from the sensor or antenna.

The haptic control module 134 obtains haptic data corresponding to thehaptic effect identified by the haptic determination module 126. Asnoted herein, the haptic data corresponds to the determined hapticeffect and define parameters or electrical characteristics used togenerate the haptic actuation signal applied to the haptic actuator 102.The haptic control module 134 can obtain the haptic data from memory orcalculate the haptic data. The haptic control module communicates thehaptic data to the I/O controller 120, which then generates a hapticsignal embodying the haptic data. The I/O controller communicates thehaptic signal to the Actuator Drive Circuit 114 which amplifies thehaptic signal to generate the haptic actuation signal and applies thehaptic actuation signal to the actuator 102. The I/O controller 120 andthe actuator drive signal may perform additional processing to thehaptic data, haptic signal, and actuator drive signal.

The communication module 130 facilitates communication between thecontroller 104 and remote devices. Examples of remote devices includecomputing devices, sensors, other wearable articles, networkingequipment such as routers and hotspots, vehicles, exercise equipment,and smart appliances. Examples of computing devices include servers,desktop computers, laptop computers, tablets, smartphones, homeautomation computers and controllers, and any other device that isprogrammable. The communication can take any form suitable for datacommunication including communication over wireless or wired signal ordata paths. In various embodiments, the communication module mayconfigure the controller 104 as a centralized controller of wearablearticles or other remote devices, as a peer that communicates with otherwearable articles or other remote devices, or as a hybrid centralizedcontroller and peer such that the controller can operate as acentralized controller in some circumstances and as a peer in othercircumstances.

Alternative embodiments of the program modules are possible. Forexample, some alternative embodiments might have more or fewer programmodules than the event detection module 124, haptic determination module126, communication module 130, and haptic control module 134. Forexample, the controller 104 can be configured to deliver only a singlehaptic effect. Such embodiments might not have a haptic determinationmodule 126, and the event detection module 124 or some other modulewould cause the haptic control module 134 to send only a single set ofhaptic data to I/O controller 120. In other alternative embodiments,there is no event detection module 124 and the haptic control module 134sends haptic data to the I/O controller 120 upon the controller 104receiving any input from the sensor 112.

In some possible embodiments, one or more of the program modules are inremote devices such as remote computing devices or other wearablearticles. For example, the event determination module 124 can be locatedin a remote computing device, which also stores a library of eventscorresponding to haptic effects and rules that define when to deliver ahaptic effect. In such an embodiment, the controller 104 communicatesdata to the remote device when the event detection module 124 determinesthat a haptic effect should be delivered through the actuator 102. Thedata might be as simple as a flag indicating that the controller 104received an input from the sensor 112, or more complex such asidentifying the type of condition indicated by the sensor 112 oridentifying the type of sensor 112 from which an input signal wasreceived. The haptic determination module 126 on the remote device willprocess the data and instructions, retrieve matching haptic data frommemory 122, and then transmit the haptic data to the controller 104 forprocessing and generating a haptic effect through the actuator 102. Inyet other possible embodiments, the event detection module 124 is alsolocated in a remote device, in which case the controller 104communicates data to the remote device when it receives input from thesensor 112.

In one embodiment, the haptic enabled article 100 further includes anetwork interface controller (NIC) 108. An antenna 113 is in electricalcommunication with the NIC 108 and provides wireless communicationbetween the controller 104 and remote devices. The communication module130 is programmed to control communication through the antenna 113including processing data embodied in signals received through theantenna 113 and preparing data to be transmitted to remote devicesthrough the antenna 113. Communication can be according to any wirelesstransmission techniques including standards such as Bluetooth, cellularstandards (e.g., CDMA, GPRS, GSM, 2.5G, 3G, 3.5G, 4G), WiGig, IEEE802.11a/b/g/n/ac, IEEE 802.16 (e.g., WiMax).

The NIC 108 also can provide wired communication between the controller104 and remote devices through wired connections using any suitable portand connector for transmitting data and according to any suitablestandards such as RS 232, USB, FireWire, Ethernet, MIDI, eSATA, orthunderbolt.

FIG. 3 is a block diagram illustrating a networked environment 141 inwhich the haptic enabled article 100 illustrated in FIGS. 1 and 2 canoperate. As illustrated, the haptic enabled article 100 can operatewithin and communicate with a network 140 and remote devices. Examplesof remote devices include computing devices 142, sensors 112, and otherremote devices 143 such as other wearable articles, medical devices,fitness monitors and equipment, vehicles, smart appliances, and otherdevices. In other embodiments, the network 140 provides datacommunication with different combinations of remote devices or remotedevices other than those disclosed herein.

The network 140 operates in an environment 141 in which the hapticenabled article 100 would be worn such as in a building, an automobileor other vehicles, or a defined area in the outdoors. Additionally, invarious embodiments, the network 140 is a public network, privatenetwork, local area network, wide area network such as the Internet, orsome combination thereof.

In various embodiments, the computing device 142 communicates with thecontroller 104 on the haptic enabled article 100. In such embodiments,the computing device 142 executes program modules to process data andcommunicates data to the controller 104. For example, the computingdevice 142 receives input from a sensor 112, which could be in thehaptic enabled article 100 or remote from the haptic enabled article100. The computing device 142 then communicates the sensor data to thecontroller 104 in the haptic enabled article 100 for processing andgeneration of the haptic actuation signal. In another example, thecomputing device 142 receives data from one wearable article and relaysthat data to the controller in another wearable article to coordinatethe delivery of haptic effects between different wearable articles. Inanother example, the computing device 142 receives data from otherremote device 143 such as a smart appliance or exercise equipment andrelays that data to the controller in the wearable article. In yetanother possible embodiment, the controller 104 in the haptic enabledarticle 100 communicates data such as sensor readings to the computingdevice 142, which then determines whether to deliver a haptic effect orwhat haptic effect to deliver. The computing device 142 then returnsappropriate data to the controller 104. Additionally, in variousembodiments, the haptic data defining the haptic effect and defining theparameters for the haptic actuation signal can be determined by thecomputing device 142

Referring now to FIGS. 4A and 4B, the actuator 102 includes a substrate202 defining a channel 204 and a reservoir 210 in fluid communicationwith the channel 204. A fluid 205 is held within the reservoir 210 andselectively flows from the reservoir 210 and through the channel 204,and then back into the reservoir 210.

First and second electrodes 201 and 203 are positioned proximal tooppositely disposed portions of the substrate 202. When an electricalpotential is applied to the first and second electrodes 201 and 203,they generate an electrical field. The first and second electrodes 201and 203 are arranged and sized so that when they are energized with apredetermined electrical potential, the channel 204 and reservoir 210will be positioned entirely within the electrical field, although inalternative embodiments portions of the channel may be located outsideof the electric field. Additionally, although the first and secondelectrodes 201 and 203 are illustrated as being proximal to oppositelydisposed portion of the substrate, the electrodes 201 and 203 can haveany position such that the channel 205 is exposed to an electric fieldgenerated between the electrodes.

The substrate has oppositely disposed end portions 200 a and 200 b andoppositely disposed edge portions 207 a and 207 b. In thisconfiguration, the substrate 202 has a length, l, substantially longerthan its width, w. However, other embodiments have different shapes forthe substrate 202. For example, the substrate 202 can be square, round,or irregularly shaped. The thickness or depth, d, of the substrate 202can vary in various configurations. For example, the thickness d candepend on the size (e.g., diameter) of the channel 204. In an exampleembodiment, the thickness or depth, d, of the substrate 202 is about 2mm when the channel 204 has a diameter of 0.7 mm. The substrate 202 isat least partially made of flexible and dielectric material. Examples ofmaterials that can be used to form the substrate include elastomers,such as Elastosil available from Wacker Chemie AG (Munich, Germany).

In the exemplary embodiment illustrated in FIGS. 4A and 4B, the channel204 has a plurality of parallel columns that form a generally zigzagpath that provides a fluid path back and forth from end-to-end 200 a to200 b and from edge-to-edge 207 a to 207 b. In this configuration, whenthe channel 204 is substantially filled with the fluid 205,substantially the entire substrate 202 has an increased stiffness.Increasing stiffness over substantially all of the substrate 202 willincrease the haptic sensation transmitted to a user and make it morelikely the user will feel the substrate 202 changes stiffness. Althougha zigzag path for the channel 204 is illustrated, other embodiment canhave other configurations such as a straight line, spiral paths,rectangular or circular paths, or any other path. Additionally, thechannel 204 can extend across substantially the entire length and widthof the substrate 202 as illustrated or across only a portion of thelength and width of the substrate 202. The total length of the channel204 and/or the number of columns in which the channel 204 is arrangedare chosen depending on the length and width of the substrate 202 and adesired strength of haptic effect. For example, the more area of thesubstrate 202 covered by the channel 204 and the longer the channel 204,the stronger the haptic effect.

In an exemplary embodiment, the channel 204 has a diameter of about 0.1mm to about 5 mm, which can vary depending on factors such as the typeof the fluid or manufacturing tolerances. A factor that may be used todetermine the cross-sectional diameter of the channel includes providingenough volume of fluid 205 in the channel 204 to change the stiffness ofthe substrate 202 an amount noticeable by a user. Another factor thatmay affect the cross-sectional area of the channel 204 is providing arelationship between the total surface tension of the fluid 205,interfacial tension between the fluid 205 and the wall of the channel204, and cross-sectional area of the channel 204 that permits control ofa capillary action of the fluid 205 and channel 204. Other embodiments,however, may not rely on capillary action to move the fluid 205 withinthe channel 204.

The reservoir 210 is sized so it has a volume equal to or greater thanthe total volume of the channel 204. In this embodiment, the reservoir210 can hold enough fluid 205 to fill the channel 204. In alternativeembodiments, the reservoir 210 has a volume smaller than the totalvolume of the channel 204.

Additionally, the reservoir 210 can hold a volume of fluid 205 that isequal to or smaller than the volume of the reservoir 210 so that all ofthe fluid 204 can be withdrawn from the channel 204 and held in thereservoir 210. Alternative embodiments can hold a volume of fluid 205that is greater than the volume of the reservoir 210 so that some fluid205 is still in the channel 204 when the reservoir 210 is completefilled. Yet another embodiment, the entire reservoir 210 and channel 204are filled with fluid 205, but not enough fluid 205 that it is underpressure and increases the stiffness of the substrate 202. Because thereservoir 210 and channel 204 are filled with fluid 205, propellingadditional fluid 205 from the reservoir 210 to the channel 204 increasesthe pressure of the fluid 205 more quickly than if the channel 204 firstneeds to be filled, which enables delivering a haptic effect morequickly.

The fluid 205 within the reservoir 210 and channel 204 can be any typeof fluid that flows when subject to an external force such as anelectric field or magnetic field. In at least some embodiments, thefluid 205 is non-compressible. In at least some embodiments, the fluid205 is a liquid metal capable of phase shifting so that its oxidationcan be controlled by exposure to electric fields. Eutectic gallium andindium (EGaIn) is an example of such a liquid metal. An example mixtureof gallium and indium is 75% gallium and 25% indium with conductivity of3.4×10⁶ S/m. An advantage of EGaIn is that it is nontoxic as compare toother liquid metals such as mercury. Examples of other phase-shiftingliquid metals include mercury, francium, cesium, gallium, rubidium, andalloys of these materials.

In other embodiments, the fluid 205 is a liquid that changes itsstiffness after changing its phase to solid (i.e., liquid-solidtransition). For example, the fluid 205 contains a liquid metal that canchange shape into a solid below a predetermined temperature, or a liquidthat can be crystallized at a predetermined temperature. In otherexamples, the fluid 205 includes a liquid that has yield strength suchthat the fluid 205 becomes liquid if an external shear stress is higherthan the yield strength. In yet other examples, an ionic liquid isselected to induce some reversible change in mechanical properties ormicrostructure of the fluid 205, such as liquid metals.

Referring to FIG. 5, another embodiment of the actuator 102 is similarlyconfigured as the actuator 102 as described in FIGS. 4A and 4B andfurther includes a second reservoir 211 for an electrolyte 206. In thisembodiment, the electrodes 201 and 203 are in contact with the firstreservoir 210 and the second reservoir 211, respectively, eitherdirectly or through, for example, wires 209. For brevity, thedescription of the other elements and configurations are omitted.

Referring now to FIGS. 6A-6D, when the fluid comprises certain metals orother materials, the channel 204 also can be loaded with an electrolyte206. In this embodiment, when the actuator 102 is in its relaxed state,the reservoir 210 is loaded with the liquid metal 205 and the channel204 is loaded with an electrolyte 206. In the embodiment of FIG. 5, thefirst reservoir 210 is loaded with the liquid metal 205, and the secondreservoir 211 is loaded with the electrolyte 206. An advantage of usingan electrolyte is that it can selectively cause the fluid to oxidize,which reduces the surface tension between the fluid 205 and the wall ofthe channel 204 and makes it easier to move the fluid through thechannel 204. Examples of an electrolyte that can be used include sodiumhydroxide (NaOH), sodium chloride (NaCl), or other conductive solutionscontaining sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), magnesium(Mg²⁺), chloride (Cl⁻), hydrogen phosphate (HPO₄ ²⁻), and hydrogencarbonate (HCO₃ ⁻) and etc. Other embodiments may not include anelectrolyte in the channel 204. Although the exemplary embodimentillustrates an electrolyte loaded in the channel with the fluid 205,other embodiments will not include an electrolyte or any other fluidother than fluid 205.

In operation, the channel 204 can be loaded with the fluid 205 such asEGaIn on the side of the first reservoir 210 and with an electrolyte 206on the side of the second reservoir 211. The first reservoir 210 isconnected to the first electrode 201 and the second reservoir 211 isconnected to the second electrode 203. A power supply through the firstand second electrodes generates an electrical potential between thefirst and second reservoirs. In some embodiments, the electricalpotential is a DC potential. Application of a positive DC potential tothe fluid 205 injects the fluid into the channel and displaces theelectrolyte in the channel. Reversing the voltage polarity causes thefluid 205 to withdraw toward the first reservoir 210. The speed of themovement of the fluid 205, such as EGaIn, can vary with the appliedbias. By way of example, where the channel has 0.7 mm inner diameter,the EGaIn can withdraw from the channel at 3.6 mm/s using −0.7 V. Thesame channel can require a +7.7 V bias to inject the EGaIn at 0.6 mm/srate. The larger voltage is necessary to drive oxidation of the surfaceand to overcome the potential drop through the electrolyte in thechannel.

When an electrical potential is applied between the first and secondreservoirs 210 and 211, the electric field causes the fluid 205 tooxidize such that oxide forms on the surface of the liquid metal. Theelectrolyte 206 then forms a slip layer between the oxide and the wallsof the channel 204 and reduces the interfacial tension between the EGaInand the wall of the channel 204.

Additionally, the oxidation lowers the surface tension and energy of thefluid 205 so that it can flow past the electrolyte 206. As the surfacetension and energy of the fluid 205 decreases, the Laplace pressure ofthe fluid 205 decreases relative to the electrolyte 206. The oxidationchanges the surface energy of the fluid 205 (e.g., liquid metal) at theinterface with ionic solution (e.g., the electrolyte 206). Prior toapplying an external voltage, the fluid 205 in the reservoir 210 cannotmove to the channel 204 due to the capillary effect resulting from theionic solution (e.g., the electrolyte 206). When an external voltage isapplied, the surface tension of the fluid 205 changes at the interfaceand, thus, can overcome the capillary effect from the ionic solution(e.g., the electrolyte 206) and move into the channel 204. Asillustrated in the sequence illustrated from FIGS. 6A to 6B, themovement of the fluid 205 into the channel 204 causes it to stiffen thesubstrate 202. As the fluid 205 moves through the channel 204 theelectrolyte 206 is displaced into the periphery areas from where theliquid metal was moved as illustrated in FIG. 6B. Enough fluid 205 flowsinto the channel 204 so that it is under pressure and it increases thestiffness of the substrate 202. When polarity of the electricalpotential is switched to negative, the oxide is removed from the surfaceof the fluid 205 and its surface tension increases, which decreases thesurface area to volume ratio of the fluid 205. As the surface tensionincreases, the Laplace pressure of the fluid 205 decreases relative tothe electrolyte 206. As illustrated in the sequence illustrated fromFIGS. 6C to 6D, the fluid 205 then moves in the opposite direction backinto the reservoir 210, which reduces the stiffness and increases theflexibility of the substrate 202.

The actuator 102 can be tuned by adjusting the amplitude of the voltageapplied across the first and second electrodes 201 and 203. As theamplitude of the voltage increases, the strength of the electric fieldincreases and the fluid 205 will flow faster and exert a greaterpressure against the substrate 202. This greater pressure will cause agreater stiffness of the substrate 202 and create a stronger hapticeffect against the user's body. Additionally, the fast flow of the fluid205, which is caused by the increased electric field, will decrease thelag time between application of the electric potential across the firstand second electrodes 201 and 203 and movement of the fluid 205 into thechannel 204. This decreased lag time provides a quicker response timefor increasing the stiffness of the substrate 202 and quicker deliveryof a haptic effect to the user. Additionally, in an exemplaryembodiment, the flow rate and pressure of fluid 205 in the channel 204can be determined by Poiseuille's law. By way of example, when 0.7 Voltsis applied to the electrodes, Poiseuille's law calculates that the EGaInexerts a force of 0.1 N against a channel wall when flowing through achannel having a diameter of 2 mm at a velocity of 20 cm/sec.

Referring now to FIG. 7, a stiffness of the substrate 202 can becalculated with a parametric formulation as an example. In thisillustration, the substrate 202 is configured as an elastomer strap. Itis noted that the force is a shear force with a moving force location oraction point. The action point of the shear force moves because a higherdensity mass (e.g., fluid 205) is moving through a lower density mass(e.g., electrolyte 206). As illustrated, a vertical maximum displacement(δ_(MAX)) at the free end of the substrate 202 is described as followsin equation (1):

$\begin{matrix}{\delta_{{MA}\; X} = \frac{{Fl}^{3}}{3{EI}}} & (1)\end{matrix}$where F is a force, l is a length of the substrate 202, E is Young'smodulus, and l is the second moment of area. A stiffness (k) of thesubstrate can then be calculated as follows in equation (2):

$\begin{matrix}{k = {\frac{3{EI}}{l^{3}} = \frac{3E\;\frac{{wt}^{3}}{12}}{l^{3}}}} & (2)\end{matrix}$where

${I = \frac{{wt}^{3}}{12}},$w is a width of the substrate, and t is a thickness of the substrate. Inan example design, where E=0.05×10⁹, w=20 mm, t=3 mm, and l=100 mm, k iscalculated to be 6.75 N/m.

FIG. 8 illustrates an alternative embodiment of the actuator 102. Inthis embodiment, the actuator 102 has an actuation portion 222 and anon-actuation portion 224. The actuation portion 222 includes a portionof the substrate 202 in which the channel 204 is defined as disclosed inmore detail herein. The non-actuation portion 224 does not define achannel 205. In this embodiment, the actuation portion 222 of theactuator 102 can be selectively stiffened to generate a haptic effect,while the non-actuation portion 224 remains compliant.

FIGS. 9A and 9B illustrate other alternative embodiments of the actuator102. In these embodiments, the actuator 102 includes first and secondchannels 232 and 234, which are substantially similar to the channel205. The first channel 232 (e.g., upper channel) is positioned proximalone surface 240 a of the substrate 202 and the second channel 234 (e.g.,lower channel) is spaced from the first channel 232 and positionedproximal an opposite surface 240 b of the substrate 202 in alayered-type of arrangement. In the illustrated embodiment, the firstand second channels 232 and 234 directly oppose each other and runparallel to each other. In alternative embodiments, however, the firstand second channels 232 and 234 do not directly oppose each other andrun orthogonally to each other, at an angle to each other, or in someother orientation relative to each other. In other embodiment, the firstand second channels 232 and 234 can have any suitable positionedrelative to each other. Other embodiments may have more than twochannels. The independent channels 232 and 234 can be controlledtogether and in unison to create a stronger tactile sensation orcontrolled independently to create a greater variety of tactilesensations. Additionally, the first and second channels can be in fluidcommunication with a common reservoir for the fluid 205, or each channel232 and 234 are in fluid communication with separate reservoirs.

As illustrated in FIG. 9A, the first and second channels 232 and 234 arepositioned in planes that run parallel to each other and thus do notcross paths. In an alternative embodiment as illustrated in FIG. 8B, thepaths of the first and second channels 232 and 234 cross over each otherat least one point within the substrate 202.

FIG. 10 is a schematic diagram of another exemplary embodiment of thehaptic actuator 102. In this embodiment, the substrate 202 of theactuator 102 includes a main portion 251 and one or more contactportions 252 ₁-252 _(n) that are positioned along one surface of thesubstrate 202 that is intended to be positioned against or otherwiseopposing a user's skin when the article 100 is worn by the user. Thecontact portions 252 ₁-252 _(n) are configured to be less stiff and moreflexible than the main portion 251 of the substrate 202. In exemplaryembodiments, the contact portions 252 ₁-252 _(n) are made of one or morematerials different than the material used to form the main portion 251of the substrate. As illustrated, the contact portions 252 ₁-252 _(n)can include a plurality of pieces that are attached to the surface ofthe main portion 251 in a desired arrangement, or can include aplurality of protrusions that are integrally formed in a desiredarrangement along the surface of the main portion 251. The contactportions 252 ₁-252 _(n) provide a softer and more comfortable feelagainst a user's skin than the main portion 251 of the substrate, butstill provide a tactile sensation to the user for the haptic effect.Alternatively, the contact portions 252 ₁-252 _(n) can be stiffer andless flexible than the main portion 251.

In alternatives to the embodiment illustrated in FIG. 10, one or moreportions of the channel 204 can run from the main portion 251 of thesubstrate 202 and through or near one or more of the contact portions252 ₁-252 _(n). The portions of the channel 204 that pass through ornear the contact portions 252 ₁-252 _(n) can have a different diameterthan the portions of the channel 204 that pass the main portion 251. Forexample, the portions of the channel 204 that pass through or near thecontact portions 252 ₁-252 _(n) can have a smaller diameter than theportions of the channel 204 that pass the main portion 251.

FIG. 11A is a schematic diagram of yet another exemplary embodiment ofthe haptic actuator 102. In this embodiment, the fluid 205 in thereservoir 210 and channel 204 is a liquid that contains molecules havingferrous properties so they are attracted to magnetic fields.Alternatively, the fluid 205 might be a ferrofluid that becomesmagnetized in the presence of a magnetic field or other colloidalsuspension having microscopic or nanoparticles that are disbursedthroughout the liquid and do not settle. The fluid 205 also can be amagnetorheological fluid or other solution having suspended ferrousparticles.

In this embodiment, coils 262 and 264 are positioned at opposite ends ofthe channel 204. In operation, the coils are wound in oppositedirections so that the flux fields emanating from the energized coilspoint in the same direction and do not cancelled each other and arewired to the actuator drive circuit 114 so they have the same polarity.Alternatively, the coils 262 and 264 are wound in opposite directionsand are wired to the actuator drive circuit 114 so they have oppositepolarities. In operation, the coils 262 and 264 are energized, whichcreates a magnetic field that applies a magnetic force to the fluid 205and causes it to move from the reservoir 210 and into the channel 204,which stiffens the substrate 202. The polarity of the coils 262 and 264can be reversed, which reverses the direction or polarity of themagnetic field. The reversed polarity of the magnetic field causes thefluid 205 to flow from the channel 204 back into the reservoir 210,which reduces the stiffness and increases the flexibility of thesubstrate 202. Alternative embodiments might use only a singleelectrical coil.

FIG. 11B illustrates yet another alternative embodiment of the actuator102. In this embodiment, a pump 266 such as an electromechanical pump,is in fluid communication with a reservoir and the channel 204. The pump266 can be on a microelectromechanical (MEMS) or even ananoelectromechanical scale (NEMS). In operation, the actuator drivecircuit 114 applies the drive signal to the pump to move the fluid 205from the reservoir 210 to the channel 205 and then back from the channel205 to the reservoir 210.

The actuator 102 disclosed herein, can be used in a variety ofapplications and in a variety of different haptic enabled articles 100.FIGS. 12-14 illustrate some of the many example applications of thehaptic enabled article 100 as described herein.

The various embodiments of the haptic actuator 102 disclosed herein canbe manufactured in various manners. In one manufacturing method, mold iscreated with a 3D printer. The mold is configured to provide the channelfor the fluid. During manufacturing, one or more materials for thesubstrate are prepared and poured into the mold. After the materials arecured, the channel is filled with the fluid 205. The electrolyte isfirst injected into the channel. The liquid metal is then injected intothe channel. In an alternative method, the actuator is directly producedby 3D printing. In this method, the 3D printer is used to form thesubstrate. As the substrate is being formed, the 3D printer will formthe channel by printing the substrate material around the location ofthe channel. Additionally, the 3D printer will deposit the fluid in thechannel as it is defined by channel. In this embodiment, the 3D printerwill alternate between printing the substrate material and printing thefluid into the channel depending on whether the print head is locatedover an area designated for the substrate or an area designated for thechannel.

Referring now to FIG. 12, the haptic-enabled article 100 is a wristwatch300 having a watch strap 302. The actuator 102 is embedded in the watchstrap 302. The controller 104 can be located in the wristwatch 300 or inthe watch strap 302. In operation, when the controller 104 receives aninput corresponding to a haptic event, it actuates the actuator 102. Theliquid flows into the channels 205 of the substrate 202 causing it tostiffen, which in turn causes the watch strap 302 to stiffen. The usercan feel the watch strap 302 stiffen around their wrist thereby beingnotified of the information embodied in the haptic effect. An exampleoperation is a smart watch that receives text messages actuates thehaptic actuator 102 notifying the user that a new message has beenreceived. Another example might be a wristwatch 300 that has an alarmfunction. The wristwatch 300 will actuate the haptic actuator 102 whenthe alarm is triggered thereby notifying the user. Other examples, mightinvolve activity or fitness trackers that actuate the haptic actuator102 when certain events occur such as a measured heart rate rising abovea threshold level (e.g., heart monitor function) or a certain numbersteps being taken by the user (e.g., pedometer function).

FIG. 13 illustrates another example in which the haptic-enabled article100 is a garment 310 such as a shirt or a jacket. In this example, thehaptic actuator 102 and controller 104 are positioned along the insidesurface of the garment 310 so it is not visible to other people,although they can be located anywhere on the garment 310. In variousembodiments, the haptic actuator 102 and the controller 104 can bemounted on a patch (not shown) that is in turn mounted on the garment310, or the haptic actuator 102 and controller 104 can be connecteddirectly to the fabric of the garment 310 itself. Additionally, theactuator 102 can be positioned at a variety of locations on the garmentincluding collars, cuffs, and the main panel of the garment 310. FIG. 14illustrates another example in which the haptic actuator 102 is mountedon a necktie 321 along one or more portions of the tie 321 that islikely to be positioned around the user's neck and under the collar 323of a dress shirt 325. In this embodiment, the necktie 321 tightensaround the user's neck when the actuator 102 becomes stiffer uponactuation thus delivering the haptic effect.

As described herein, the methodology and/or configurations of thepresent disclosure are used in various applications. For example, thehaptic enabled device 100 of the present disclosure is applicable in avibrating system. The methods described herein can be used to change thestiffness of a vibrating system. As the stiffness of a vibrating systemchanges, a vibrating system can have different resonant frequencies,thereby providing different haptic outputs.

The various examples and teachings described above are provided by wayof illustration only and should not be construed to limit the scope ofthe present disclosure. Those skilled in the art will readily recognizevarious modifications and changes that may be made without following theexamples and applications illustrated and described herein, and withoutdeparting from the true spirit and scope of the present disclosure.

What is claimed is:
 1. A haptic enabled apparatus comprising: a fluidincluding a liquid metal; an electrolyte; a substrate being at leastpartially flexible and defining a channel, the fluid and the electrolytebeing positioned within at least a portion of the channel, and a portionof the substrate proximal to the fluid being stiffer than a portion ofthe substrate spaced from the fluid; and wherein the fluid moves throughthe channel and displaces the electrolyte within the channel in responseto an artificially-generated field, and a stiffness of the substratechanges in response to the fluid moving through the channel to deliver ahaptic effect.
 2. The haptic enabled apparatus of claim 1, wherein theartificially-generated field includes an electric field.
 3. The hapticenabled apparatus of claim 1, wherein the artificially-generated fieldincludes a magnetic field.
 4. The haptic enabled apparatus of claim 1,wherein the liquid metal is a gallium alloy.
 5. The haptic enabledapparatus of claim 4, wherein the liquid metal includes a eutectic ofgallium and indium.
 6. The haptic enabled apparatus of claim 1, whereinthe electrolyte is selected from the group consisting essentially ofsodium hydroxide (NaOH) and sodium chloride (NaCl).
 7. The hapticenabled apparatus of claim 1, wherein the fluid includes a ferrofluid.8. The haptic enabled apparatus of claim 1, further comprising: firstand second electrodes, the first and second electrodes positioned atopposite ends of the channel; and the liquid metal flows through thechannel in one direction when an electrical potential having a polarityis applied to the first and second electrodes; and the liquid metalflows through the channel in an opposite direction when an electricalpotential having an opposite polarity is applied to the first and secondelectrodes.
 9. The haptic enabled apparatus of claim 8, wherein thefirst and second electrodes are connected to the opposite ends of thechannel.
 10. The haptic enabled apparatus of claim 8, wherein the liquidmetal flowing through the channel in the one direction deposits oxideson a surface of the liquid metal that interfaces with the electrolyte,and the liquid metal flowing through the channel in the oppositedirection removes the oxides from the surface of the liquid metal. 11.The haptic enabled apparatus of claim 8 further comprising: a controllerelectrically connected to the first and second electrodes, thecontroller configured to apply an electrical potential across the firstand second electrodes in response to a drive signal, the electricalpotential corresponding to movement of the fluid and to information forcommunication to a user.
 12. The haptic enabled apparatus of claim 11,wherein the electrical potential has an amplitude in the range of about−0.7 V to about +7.7 V.
 13. The haptic enabled apparatus of claim 12,wherein the electrical potential has at least one electricalcharacteristic corresponding to the information for communication to auser, the at least one electrical characteristic selected from the groupconsisting essentially of frequency, amplitude, phase, inversion,duration, waveform, attack time, rise time, fade time, lag time relativeto an event, and lead time relative to an event.
 14. The haptic enabledapparatus of claim 1, further comprising: a wearable article, thesubstrate being operably connected to the wearable article.
 15. Thehaptic enabled apparatus of claim 1, wherein the substrate furtherdefines a reservoir in fluid communication with the channel.
 16. Thehaptic enabled apparatus of claim 15, wherein the substrate comprises: afirst channel and a second channel separate from the first channel, thefirst channel having a path that crosses over a path of second channelat least one point within the substrate.
 17. The haptic enabledapparatus of claim 15, wherein the substrate includes a main portion anda contact portion, the contact portion having lower stiffness than themain portion.
 18. A method of automatically generating a haptic effect,the method comprising: generating an artificially-generated field, theartificially-generated field embodying information to communicate to auser through a haptic effect; moving fluid through a channel defined ina flexible substrate and displaces an electrolyte within the channel inresponse to the artificially-generated field, the fluid including aliquid metal; increasing a stiffness of at least a portion of theflexible substrate in response to the fluid moving through the channel,the increasing of the stiffness generating the haptic effect andcommunicating the information.
 19. The method of claim 18, wherein theartificially-generated field includes an electric field.
 20. The methodof claim 18, wherein the artificially-generated field includes amagnetic field.
 21. The method of claim 18 further comprising:generating an electrical signal, the electrical signal embodying theinformation to communicate to a user through the haptic effect; applyingthe electrical signal to first and second electrodes to generate theartificially-generated field; and applying the artificially-generatedfield to the channel defined in the flexible substrate and the fluid.22. The method of claim 18 wherein moving the fluid through the channelin response to the artificially-generated field comprises: moving fluidthrough the channel in one direction when the artificially-generatedfield has a first polarity; and moving fluid through the channel in anopposite direction when the artificially-generated field has an oppositepolarity.
 23. The method of claim 22 wherein: moving the fluid throughthe channel in one direction comprises depositing oxides on a surface ofthe liquid metal; and moving the fluid through the channel in theopposite direction comprises removing the oxides from the surface of theliquid metal.
 24. The method of claim 22 wherein: moving fluid throughthe channel in one direction comprises increasing the stiffness of theflexible substrate; and moving fluid through the channel in the oppositedirection comprises decreasing the stiffness of the flexible substrate.25. A haptic enabled apparatus wearable by a person, the apparatuscomprising: a wearable article; a fluid, the fluid being responsive toan artificially-generated field, the fluid comprising a liquid metal andan electrolyte; a substrates operably connected to the wearable article,the substrate being at least partially flexible and defining a channel,the fluid being positioned within at least a portion of the channel anda portion of the substrate proximal to the fluid being stiffer than aportion of the substrate spaced from the fluid; first and secondelectrodes, the first and second electrodes positioned proximal toopposite ends of the channel; a controller electrically connected to thefirst and second electrodes, the controller configured to generate anelectrical signal, the electrical signal embodying information tocommunicate through a haptic effect, the electrical signal generatingthe artificially-generated field when applied to the first and secondelectrodes; wherein, when the artificially-generated field has onepolarity, an oxide is deposited on the liquid metal and the liquid metalflows through the channel in one direction and increases a stiffness ofthe substrate to deliver the haptic effect and communicate theinformation; and wherein, when the artificially-generated field has anopposite polarity, the oxide is removed from the liquid metal and theliquid metal flows through the channel in an opposite direction and thestiffness of the substrate is decreased.